2005/12/12 by Daniele Oriti · 1 citation
Physics and Astronomy · #gr-qc
paper · pdf · doi:10.1103/physrevd.73.061502
published as Phys.Rev. D73 (2006) 061502 · RevTeX; 6 pages, 2 figures
arxiv created 2005/12/12 · arxiv updated 2009/12/01
We construct a generalised formalism for group field theories, in which the domain of the field is extended to include additional proper time variables, as well as their conjugate mass variables. This formalism allows for different types of quantum gravity transition amplitudes in perturbative expansion, and we show how both causal spin foam models and the usual a-causal ones can be derived from it, within a sum over triangulations of all topologies. We also highlight the relation of the so-derived causal transition amplitudes with simplicial gravity actions.